Researchers in the UK say they have injected lab-grown blood into people for the first time.
They are studying how long these lab-grown blood cells can last compared with those made inside a donor’s body.
The clinical trial is a key first step towards making lab-grown red blood cells available for patients who frequently need transfusions, or who have rare blood types that are hard to source from donors.
How is this lab-grown blood made?
Donors were recruited from Britain’s National Health Service (NHS) blood donor base. They donated blood to the trial and stem cells were separated out of the samples.
These stem cells were then grown in an NHS laboratory in Bristol to produce red blood cells, which carry oxygen from the lungs to the rest of the body.
The trial is being led jointly by NHS Blood and Transplant and the University of Bristol.
The researchers are starting with small amounts - around 5-10 ml, or about one to two teaspoons - to see how it performs inside the human body.
So far, two people have been transfused with the lab-grown red cells. No unexpected side effects were reported and the patients are “well and healthy,” the team said in a statement.
The trial aims to test the lab-grown blood in at least 10 healthy volunteers.
The recipients' identity is being withheld to help keep the trial "blinded". In other words, the patients themselves don’t know whether they have received lab-grown blood or standard blood, so as not to influence the study’s findings.
Reducing the need for transfusions
The hope is that because the lab-grown cells are so freshly made, they’ll actually perform better than standard blood donations.
Red blood cells typically last for around 120 days before they need to be replaced, and a typical blood donation contains a mix of cells of varying ages.
If the lab-grown cells turn out to last longer in the body, patients who regularly need blood may not need transfusions as often. That would reduce the iron overload caused by frequent blood transfusions, which can lead to serious complications, says the team.
The researchers working on the trial called it "challenging and exciting".
"The need for normal blood donations to provide the vast majority of blood will remain. But the potential for this work to benefit hard-to-transfuse patients is very significant," Dr Farrukh Shah, Medical Director of Transfusion for NHS Blood and Transplant, said in a statement.
Among those set to potentially benefit are patients with sickle cell disease - a type of inherited red blood cell disorder where blood cells become hard and sticky and die early, causing other serious complications such as pneumonia and strokes.
These patients typically require frequent blood transfusions to lessen their anaemia and help their blood flow more freely, but they may develop resistance against the transfused blood, which then causes the treatment to fail.
"This research offers real hope for those difficult-to-transfuse sickle cell patients who have developed antibodies against most donor blood types," said John James, Chief Executive of the Sickle Cell Society.
"However, we should remember that the NHS still needs 250 blood donations every day to treat people with sickle cell and the figure is rising.
"The need for normal blood donations to provide the vast majority of blood transfusions will remain. We strongly encourage people with African and Caribbean heritage to keep registering as blood donors and start giving blood regularly".